Facile Preparation of Highly Active CO2 Reduction (001)TiO2/Ti3C2Tx Photocatalyst from Ti3AlC2 with Less Fluorine

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To date, (001)TiO2/Ti3C2Tx hybridized photocatalyst is usually prepared through the complicated treatment of Ti3AlC2 in the presence of corrosive fluorine with a molar ratio of nF:nTi of more than 20. To reduce the use of corrosive fluorine, herein, exploiting beyond the conventional method, we report a facile synthetic method for (001)TiO2/Ti3C2Tx, elaborately using HF as both an etchant for Al elimination and a morphology control agent for the growth of (001)TiO2 nanosheets, with a sharply diminished use of fluorine (nF:nTi = 4:1) and simplified operation procedures. After optimization, the resulting (001)TiO2/Ti3C2Tx heterojunction exhibited markedly high photocatalytic activity with the CO2 reduction rate of 13.45 μmol g−1 h−1, which even surpasses that of P25 (10.95 μmol g−1 h−1), while the photoelectron selectivity to CH4 is approaching 92.84%. The superior photoactivity is interpreted as the fact that Ti3C2Tx with a lower work function induces photoinduced hole transfer and suppresses the charge recombination, thus facilitating the CO2 multi-electron reduction. This study provides a novel and simple synthesis for (001)TiO2/Ti3C2Tx towards sustainable energy transformations.